Section 6. Except as the ordinance or by-law may otherwise provide in accordance with section eight or said section eight or nine, no building or structure within an historic district shall be constructed or altered in any way that affects exterior architectural features unless the commission shall first have issued a certificate of appropriateness, a certificate of non-applicability or a certificate of hardship with respect to such construction or alteration.
Any person who desires to obtain a certificate from the commission shall file with the commission an application for a certificate of appropriateness, a certificate of non-applicability or a certificate of hardship, as the case may be, in such form as the commission may reasonably determine, together with such plans, elevations, specifications, material and other information, including in the case of demolition or removal a statement of the proposed condition and appearance of the property thereafter, as may be reasonably deemed necessary by the commission to enable it to make a determination on the application.
No building permit for construction of a building or structure or for alteration of an exterior architectural feature within an historic district and no demolition permit for demolition or removal of a building or structure within an historic district shall be issued by a city or town or any department thereof until the certificate required by this section has been issued by the commission.